Oils used in industrial applications are typically petroleum based hydrocarbons that can damage the environment, as well as pose health risks to people using them. Plant oils are an environmentally friendly alternative to petroleum based products, and are based on renewable natural resources. The major components of plant oils are triacylglycerols (TAGs), which contain three fatty acid chains esterified to a glycerol moiety. The polar glycerol regions and non-polar hydrocarbon regions of TAGs are thought to align at the boundaries of metal surfaces, and thus have better lubricant properties than petroleum hydrocarbons.
The low temperature properties and oxidative stability of plant oils, however, limit their use for industrial applications. Industrial oils must be liquid and have a reasonable viscosity at low temperatures. Most plant oils do not possess such low temperature properties. For example, high erucic rapeseed oil has a pour point (i.e., the temperature at which the oil ceases to flow) of −16° C., but undergoes a significant increase in viscosity with decreasing temperatures.
Industrial oils also must have high oxidative stability, which generally is related to the degree of unsaturation present in the fatty acyl chains. Reaction of a plant oil with oxygen can lead to polymerization and cross-linking of the fatty acyl chains, and decreased oxidative stability. Saturated hydrocarbon based oils have no unsaturation and therefore have high oxidative stability.